Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description fully bears the burden of behavioral disclosure. It clearly explains the dual read/write behavior and what triggers each mode. It could mention if the original file is modified (likely returns a new PDF), but the description is transparent enough for safe usage.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short sentences, front-loaded with the core purpose. Every part is informative and there is no wasted text. It efficiently conveys read and write modes.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 6 parameters, no output schema, and no annotations, the description covers the core read/write behavior and return types. However, it does not explicitly clarify the mutual exclusivity of file_id and data_base64, nor the exact output format for write mode (e.g., what metadata fields are returned). Slight gaps remain.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so baseline is 3. The description adds critical semantics by defining the mode-switching logic: absence of write parameters means read mode, presence of any write parameter means write mode. This goes beyond the individual parameter descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool reads or writes PDF metadata, and distinguishes between the two modes by specifying conditions: without write parameters returns metadata (title, author, pages), with any write parameter writes and returns a new PDF. It is specific about the resource (PDF metadata) and the action (read/write).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context for when to use the tool (read or write metadata). However, it does not explicitly state when not to use it or mention alternative tools from the sibling list. The guidance is implied by the mode, but lacks explicit exclusions or comparisons.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.